In recent years, inter-module communication apparatuses for allowing high speed wireless data communication between a number of modules in close proximity, such as non-contact data communication between a memory card and a PC, have been developed. In addition, other types of inter-module communication apparatuses are expected to allow for wireless communication between semiconductor integrated circuit chips through packages in PoP (package on package), where a number of packages in which semiconductor integrated circuit chips are sealed are layered on top of each other.
The present inventor has proposed an electronic circuit for data communication between mounting boards or semiconductor integrated circuit chips using inductive coupling between coils formed of wires on printed circuit boards (PCBs) or in semiconductor integrated circuit chips, namely magnetic field coupling (see Non-Patent Documents 1 to 3).
In Non-Patent Document 1, inductive coupling between a coil formed of a wire in a semiconductor integrated circuit chip sealed in a package and a coil on a flexible printed circuit (FPC) mounted on the surface of the package is used to detect the data within the semiconductor integrated circuit chip sealed in the package from the outside of the package so that the data can be used for the evaluation of the semiconductor integrated circuit chip and the system formed thereof as well as debugging.
In addition, in Non-Patent Document 2, a processor semiconductor integrated circuit chip and a memory semiconductor integrated circuit chip that are layered on top of each other and mounted in one package can communicate with each other at a high speed using inductive coupling between a pair of coils, each of which is formed of a wire in the semiconductor integrated circuit chip. This technology can be applied to a structure where a package in which a processor is mounted and a package in which a memory is mounted are layered on top of each other so that the processor can read data from and write data into the memory through wireless data communication using inductive coupling between coils formed in the packages.
Furthermore, in Non-Patent Document 3, inductive coupling between a pair of coils on printed circuit boards is used so that a memory card and a PC can make non-contact data communication.
Meanwhile, proximity coupling between microstrip lines or bus lines has also been proposed for the wireless communication of data using capacitive coupling and inductive coupling (see Patent Documents 1 to 7). In Patent Document 1, differential transmission lines made of two transmission lines arranged parallel to each other can be arranged in the same direction so as to be parallel to each other so that wireless communication can be made possible between two modules.
In addition, in Patent Document 2, a moveable driver stage is electromagnetically or capacitively coupled via coupling elements to two conductors that are arranged symmetrically so that a bidirectional transmission system can be constructed.
Furthermore, in Patent Document 3, two microstrip lines arranged on a grounded plate with a dielectric film in between are used as directional couplers to input a differential signal into the two microstrip lines so that wireless communication can be made possible between two modules.
Moreover, in Patent Documents 4 to 7, two bus wires are arranged so as to be partially parallel to each other so that wireless communication can be made possible between a number of printed circuit boards through capacitive coupling and inductive coupling.